1) Field of the Invention
The present invention relates generally to a dressing for treating a penetrating chest wound, and more particularly, to an occlusive dressing that seals tightly over the would and has a fluid drainage system allowing fluid to exit from the wound while preventing fluid intake, and which carries a needle and catheter for immediate access and use in relieving a tension pneumothorax.
2) Description of Related Art
When a penetrating chest wound occurs, the negative pressure within the pleural space that prevents the lungs from collapsing during normal breathing can be disrupted, resulting in a life threatening situation. The flow of air and other fluids through the wound into the chest cavity can significantly reduce or eliminate this negative pressure. Once this occurs, the lungs lose the ability to inflate. This condition is referred to as a pneumothorax, where air can both enter and exit from the pleural space through the wound, making breathing extremely difficult. Certain penetrating chest wounds, known as a tension pneumothorax, occur when a one-way valve is formed by the wound that allows airflow into the pleural space while preventing airflow out. In a tension pneumothorax, each inhalation traps air in the chest, increasing pressure on the lungs and ultimately causing them to collapse. Additionally, the increasing pressure pushes important structures in the center of the chest, such as the heart, major blood vessels, and airways, towards the sides of the chest. This shifting can cause further compression of the lungs and may affect the flow of blood returning to the heart. These additional complications in a tension pneumothorax make it a life threatening condition that requires immediate treatment.
The prior art includes various dressings designed to prevent the intake of fluid into the chest cavity for penetrating chest wounds. However, these dressings are designed for civilian emergency medical services and were never intended for use under battlefield conditions. Common failures of these devices during combat conditions range from inadequate adhesive for attaching to the skin, insufficient size for covering exit wounds from high velocity projectiles, difficult access to the product due to packaging, and extended time being required to apply the dressing. Also, not a single dressing in the prior art attempts to address the issue of relieving a tension pneumothorax by providing the means for treating the condition in a convenient and immediately accessible package together with the dressing.
For example, U.S. Pat. No. 5,160,322 is representative of a plurality of similar type dressing which disclose an occlusive chest sealing valve that includes a plastic sheet carrying a check valve that allows fluid to exit the wound and pass through the valve but prevents fluid intake in order to maintain the negative pressure within the pleural space. A problem with this design, however, is that dirt and other debris may find its way into the valve assembly and prevent proper operation. Additionally, the adhesive used on these plastic sheet type dressings fails under the rigors of combat conditions and the dressing becomes dislodges. Also, the plastic sheet is not sufficiently flexible to adapt to the various contours of the chest to provide a sufficient seal for any extended period of time, or which can be reapplied. Further, the valve assembly increases the cost of the dressing.
U.S. Pat. No. 5,662,598, discloses another dressing for a penetrating chest wound. This design uses a gauze pad as a buffer between the skin and a flexible plastic sheet which blocks airflow into the wound. One portion of the sheet adjacent the gauze pad does not include any adhesive to allow fluid to exit from under the sheet. The gauze pad is impregnated with silicone, adding significant cost to the dressing. Further, if the non-adhesive flap portion of the dressing becomes distorted in laying flat against the skin, the dressing becomes ineffective at preventing fluid intake. Also, because of the size of the gauze pad under the sheet, there is only a small amount of adhesive for holding the dressing in place, and may be easily dislodged.
Additionally, as noted above, none of the prior art patents teach any means in association with the dressing for relieving excess pressure which may have already built up in the pleural space.
Accordingly, it is an object of the present invention to provide a dressing for a penetrating chest wound that is capable of maintaining an effective seal over the wound which blocks fluid intake while allowing fluid outflow despite exposure to dirt and debris and jostling of the patient under the extreme rigors of combat conditions.
It is a further object of the present invention to provide a dressing for a penetrating chest wound that is simple to manufacture, is easy to apply over the wound, and is lower in cost to manufacture than the dressings taught in the prior art.
It is a further object of the present invention to provide a dressing for a penetrating chest wound that includes means for relieving excess pressure that is trapped and has accumulated in the pleural space.